package main

import (
	"context"
	"encoding/json"
	"errors"
	"os"
	"path/filepath"
	"testing"

	"github.com/stretchr/testify/require"
)

// DaemonMessageTest owns test agents and the loops selected by Start.
type DaemonMessageTest struct {
	agents   DaemonAgents
	loops    []*TurnLoop
	events   []*TurnEventRecorder
	messages *DaemonMessages
	logs     *SyncBuffer
	cancel   context.CancelFunc
	done     []chan error
}

func (r *DaemonMessageTest) Start(t *testing.T, indices ...int) {
	t.Helper()

	ctx, cancel := context.WithCancel(t.Context())
	r.cancel = cancel
	for _, index := range indices {
		done := make(chan error, 1)
		r.done = append(r.done, done)
		go func() {
			done <- r.loops[index].Run(ctx)
		}()
	}
}

func (r *DaemonMessageTest) Queue(t *testing.T) DaemonMessageFile {
	t.Helper()

	data, err := os.ReadFile(r.messages.path)
	require.NoError(t, err)

	var file DaemonMessageFile

	require.NoError(t, json.Unmarshal(data, &file))

	return file
}

func (r *DaemonMessageTest) Close(t *testing.T) {
	t.Helper()

	if r.cancel != nil {
		r.cancel()

		for _, done := range r.done {
			require.ErrorIs(t, <-done, context.Canceled)
		}

		r.cancel = nil
		r.done = nil
	}

	require.NoError(t, r.agents.Close())

	r.agents = nil
}

func newDaemonMessageTest(t *testing.T, dir string, server *ModelFake) *DaemonMessageTest {
	t.Helper()

	_, err := os.Stat(filepath.Join(dir, daemonAgentDirName, "children"))
	if errors.Is(err, os.ErrNotExist) {
		daemonChildConfig(t, dir, "Garden")
		daemonChildConfig(t, dir, "Library")
	} else {
		require.NoError(t, err)
	}

	test := &DaemonMessageTest{
		logs: &SyncBuffer{},
	}
	test.agents, err = openDaemonAgents(t.Context(), dir, server.URL, ModelAPIKey(modelTestKey), defaultConfig().Compactor, newTestClock().Now, daemonTestLogger(test.logs))
	require.NoError(t, err)
	t.Cleanup(func() {
		test.Close(t)
	})

	for _, agent := range test.agents {
		events := &TurnEventRecorder{}
		loop, err := agent.Loop(nil, events.Add)
		require.NoError(t, err)

		test.events = append(test.events, events)
		test.loops = append(test.loops, loop)
	}

	test.messages, err = openDaemonMessages(test.loops)
	require.NoError(t, err)

	return test
}